The present invention relates to an arrangement for recirculation of exhaust gases of a supercharged combustion engine in a vehicle.
The technique referred to as EGR (Exhaust Gas Recirculation) is a known means of recirculating part of the exhaust gases from a combustion process in a combustion engine, via a return line, to an inlet line for supply of air to the combustion engine. A mixture of air and exhaust gases is thus supplied via the inlet line to the engine's cylinders in which combustion takes place. Adding exhaust gases to the air causes a lower combustion temperature which results inter alia in reduction of the content of nitrogen oxides (NOx) in the exhaust gases. This technique is used for both Otto engines and diesel engines. The recirculating exhaust gases are usually cooled in a so-called EGR cooler before being led to the combustion engine. An existing circulating coolant of the combustion engine's cooling system is usually used for cooling the exhaust gases in the EGR cooler.
The amount of air which can be supplied to a supercharged combustion engine depends on the pressure of the air but also on the temperature of the air. In order to supply as large an amount of air as possible to the combustion engine, the compressed air is therefore cooled before being led to the combustion engine. The compressed air is usually cooled in a charge air cooler situated at a front portion of the vehicle where it is cooled by ambient air flowing through the charge air cooler. The compressed air may be cooled to a temperature substantially corresponding to the temperature of the surroundings.
Providing such recirculation of exhaust gases involves arranging in the vehicle a return line for exhaust gases with, inter alia, an EGR cooler. Providing a supply of compressed air to the combustion engine entails arranging in the vehicle an inlet line for air with, inter alia, a charge air cooler. In a fitted state, the return line and the inlet line with their constituent components occupy a relatively large amount of space in a vehicle.